On Tue, 6 Sept 2022 at 12:41, Evgeniy Baskov <baskov@xxxxxxxxx> wrote: > > Previous calculations ignored pages implicitly mapped by ACPI code, I'm not sure I understand what this means. Which ACPI code and which pages does it map? > so theoretical upper limit is higher than was set. > > Using 4KB pages is desirable for better memory protection granularity. > Approximately twice as much memory is required for those. > > Increase initial page table size to 64 4KB page tables. > > Signed-off-by: Evgeniy Baskov <baskov@xxxxxxxxx> > --- > arch/x86/include/asm/boot.h | 26 ++++++++++++++------------ > 1 file changed, 14 insertions(+), 12 deletions(-) > > diff --git a/arch/x86/include/asm/boot.h b/arch/x86/include/asm/boot.h > index 9191280d9ea3..024d972c248e 100644 > --- a/arch/x86/include/asm/boot.h > +++ b/arch/x86/include/asm/boot.h > @@ -41,22 +41,24 @@ > # define BOOT_STACK_SIZE 0x4000 > > # define BOOT_INIT_PGT_SIZE (6*4096) > -# ifdef CONFIG_RANDOMIZE_BASE > /* > * Assuming all cross the 512GB boundary: > * 1 page for level4 > - * (2+2)*4 pages for kernel, param, cmd_line, and randomized kernel > - * 2 pages for first 2M (video RAM: CONFIG_X86_VERBOSE_BOOTUP). > - * Total is 19 pages. > + * (3+3)*2 pages for param and cmd_line > + * (2+2+S)*2 pages for kernel and randomized kernel, where S is total number > + * of sections of kernel. Explanation: 2+2 are upper level page tables. > + * We can have only S unaligned parts of section: 1 at the end of the kernel > + * and (S-1) at the section borders. The start address of the kernel is > + * aligned, so an extra page table. There are at most S=6 sections in > + * vmlinux ELF image. > + * 3 pages for first 2M (video RAM: CONFIG_X86_VERBOSE_BOOTUP). > + * Total is 36 pages. > + * > + * Some pages are also required for UEFI memory map and > + * ACPI table mappings, so we need to add extra space. > + * FIXME: Figure out exact amount of pages. > */ > -# ifdef CONFIG_X86_VERBOSE_BOOTUP > -# define BOOT_PGT_SIZE (19*4096) > -# else /* !CONFIG_X86_VERBOSE_BOOTUP */ > -# define BOOT_PGT_SIZE (17*4096) > -# endif > -# else /* !CONFIG_RANDOMIZE_BASE */ > -# define BOOT_PGT_SIZE BOOT_INIT_PGT_SIZE > -# endif > +# define BOOT_PGT_SIZE (64*4096) > > #else /* !CONFIG_X86_64 */ > # define BOOT_STACK_SIZE 0x1000 > -- > 2.35.1 >
